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Vachellia macracantha - spines

Vachellia macracantha - pet gland

Vachellia macracantha - leaf

Vachellia macracantha - inflor

Vachellia macracantha - habit

Vachellia macracantha - fruit

Vachellia macracantha - flower

Vachellia macracantha - branch

Name

Vachellia macracantha (Humboldt & Bonpland ex Willdenow) Seigler & Ebinger, Phytologia 87:160. 2005.
syn. Acacia macracantha Humb. & Bonpl. ex Willd. Sp. pl. 4:1080. 1806.

Synonymy and types

Basionym: Acacia macracantha Humb. & Bonpl. ex Willd. Sp. pl. 4:1080. 1806. - Poponax macracantha (Humb. & Bonpl. ex Willd.) Killip in Little, Caribbean Forester 9:241. 1948. - Mimosa macracantha (Humb. & Bonpl. ex Willd.) Poir. in Lam., Encycl. Suppl. 1:78. 1810. - TYPE: MEXICO. without exact locality, Humboldt & Bonpland s.n. (holotype: B-Willd., GH photo; isotypes: P, NY).

Vachillea lutea (Miller) Speg., Bol. Acad. Nac. Ci. Córdoba 26:301. 1923. - Mimosa lutea Mill., Gard. dict. ed. 8, 1768. - Acacia lutea (Mill.) Britton, Bull. Torrey Bot. Club 16:327. 1889. - Poponax lutea (Mill.) Britton & Rose, N. Amer. Fl. 23:90. 1928. - TYPE: JAMAICA, 1731 W.Houstoun s.n. (holotype: BM; isotype: K).  NOTE: Not Acacia lutea Leavenworth (1824) which is a synonym of Neptunea lutea (Leavenw.) Benth. (Correll and Johnston 1970).
 
Acacia flexuosa Humb. & Bonpl. ex Willd., Sp. pl. 4:1082. 1806. - Mimosa flexuosa (Humb. & Bonpl. ex Willd.) Poir. in Lam., Encycl. Suppl. 1:79. 1810. - Poponax flexuosa (Humb. & Bonpl. ex Willd.) Britton & Rose in Britton & Killip, Ann. New York Acad. Sci. 35:139. 1936. - TYPE: VENEZUELA. CUMANÁ; Humboldt & Bonpland 81 (holotype: B-Willd.; isotypes:  HAL, P).

Acacia flexuosa Humb. & Bonpl. ex Willd.   ambigua DC., Prodr. 2:463. 1825. - TYPE: GUADELOUPE. C.G.Bertero s.n. (holotype: G-DC).

Acacia flexuosa Humb. & Bonpl. ex Willd.   lasiocarpa Griseb., Abh. Königl. Ges. Wiss. Göttingen 7:211. 1857. - TYPE: none cited, from Guadeloupe.

Acacia obtusa Humb. & Bonpl. ex Willd., Sp. pl. 4:1087. 1806. - Mimosa obtusa (Humb. & Bonpl. ex Willd.) Poir. in Lam., Encycl. Suppl. 1:82. 1810. - TYPE: VENEZUELA. ORINOCO: Humbold & Bonpland s.n. (holotype: P-H.B.K.; isotype: B-Willd.).

Acacia punctata Humb. & Bonpl. ex Willd., Sp. pl. 4:1084. 1806. - TYPE: in America meridionali, Humboldt & Bonpland 1162 (holotype: B-Willd.).

Acacia humboldtii Desv. in W. Ham., Prodr. Pl. Ind. Occid. 60. 1825. - TYPE: none cited, from Guyana.

Acacia macracanthoides Bertero ex DC., Prod. 2:463. 1825. - Poponax macracanthoides (Bertero ex DC.) Britton & Rose, N. Amer. Fl. 23:89. 1928. - TYPE: JAMAICA. C.G.Bertero s.n. (holotype: G-DC).

Acacia subinermis Bertero ex DC., Prodr. 2:463. 1825. - TYPE: JAMAICA. C.G.Bertero s.n. (holotype; G-DC, MO photo).

Acacia microcephala Macfad., Fl. Jamaica 1:316. 1837. - TYPE: JAMAICA. at bridge beyond the second milestone on the windward road, J.Macfadyen s.n. (holotype: K). NOTE: Not Acacia microcephala Richard (1845) which has prickles and is considered a synonym of Acacia tenuifolia (L.) Willd. by Howard (1988).

Acacia platyacantha Schltdl., Linnaea 12:565. 1838. - TYPE: MEXICA. HIDALGO: Mineral del Monte, C.A.Ehrenberg s.n. (holotype: B, destroyed).

Acacia pellacantha Vogel in Meyen, Nov. Actorum Acad. Caes. Leop.-Carol. Nat. Cur. 19. Suppl. 1:45. 1843. - TYPE: PERU. Lima, Dombey, F.J.F.Meyen & Cuming1013. (holotype: not seen).

Acacia macracantha Humb. & Bonpl. ex Willd. var. glabrescens Griseb., Fl. Brit. W. I. 222. 1860. - TYPE: JAMAICA. in dry plains, Mar, J.Macfadyen s.n. (holotype: K).

Acacia macracantha Humb. & Bonpl. ex Willd. var. glabra Kitanov, Ann. Univ. Sofia Fac. Biol. 66(2):31. 1974. - TYPE: CUBA. ORIENTE: sur de Guantánamo en Novaliches, 30 Jun. 1936, Hno. León s.n.; Cuba, Prov. Oriente, Santiago de Cuba-Caney, bordes del mar en Arroyo de la Costa, 9 Sep. 1951, M.López Figueiras s.n. (syntypes: SV).
  
Mimosa atomaria Poir. in Lam., Encylc. Suppl. 1:81. 1810..-  TYPE: none cited.
 
Poponax cowellii Britton & Rose, N. Amer. Fl. 23:89. 1928. - Acacia cowellii (Britton & Rose) León in León & Alain, Contr. Ocas. Mus. Hist. Nat. Colegio "De La Salle" 9:8. 1950. - TYPE: CUBA. ORIENTE: tree 5 m with spreading branches, hillside thicket, vicinity of Santiago, 10-25 Mar. 1912, N.L.Britton, E.G.Britton & J.F.Cowell 12593 (holotype: NY).

Poponax cansecens Britton ex Britton & Killip, Ann. New York Acad. Sci. 35:139. 1936. - Acacia canescens (Britton ex Britton & Killip) García-Barriga & Forero-Gonzáles, Cat. Il. Pl. Cundinamarca 3:19. 1968. - TYPE: COLOMBIA. CUNDINAMARCA: Anapoima,  alt. 400 m, 1851-1857, J.Triana 4439 (holotype: NY). NOTE: Not Acacia canescens Martens & Galeotti (1843), a member of the genus Senegalia.

Formal description

Small tree to 10 m tall. Bark dark gray to dark brown, shallowly furrowed. Twigs light brown to reddish brown, flexuous, glabrous to densely puberulent to lanate. Short shoots usually absent, rarely poorly developed. Leaves alternate, 70-250 mm long. Stipular spines reddish brown to purplish, becoming light gray with age, symmetrical, terete to oval, straight, stout, to 60(80) mm x 1-3 mm near the base, glabrous to pubescent at the base and sometimes throughout. Petiole adaxially grooved, 5-13 mm long, glabrous to puberulent to sometimes lanate; petiolar gland solitary, located medially to just below the lower pinna pair, stalked, circular to elongated, 0.4-2.3 mm across, with a flat to globose apex, mostly glabrous. Rachis adaxially grooved, 60-240 mm long, glabrous to densely puberulent to lanate, a sessile, circular gland, 0.4-0.6 mm across, between the upper 1 to 3(8) pinna pairs. Pinnae 12 to 45 pairs per leaf, 20-45 mm long, 2-8 mm between pinna pairs. Petiolules 0.7-1.3 mm long. Leaflets 19 to 47 pairs per pinna, opposite, 0.5-1.2 mm between leaflets, linear, 1.7-4.5 x 0.5-1.3 mm, glabrous to lightly pubescent, lateral veins not obvious, only one vein from the base, base oblique, margins ciliate, apex broadly acute to obtuse. Inflorescence a densely flowered globose head 5-10 mm across, solitary or in clusters of 2 to 10 in the leaf axil. Peduncles 7-25 x 0.4-1.3 mm, glabrous to densely puberulent to lanate. Involucre 4- to 6-lobed, located at the base of the globose head, puberulent, persistent. Floral bracts spatulate, 0.8-1.4 mm long, apex puberulent, deciduous. Flowers sessile, pale yellow; calyx 5-lobed, 0.8-1.5 mm long, glabrous, the lobes sometimes puberulent; corolla 5-lobed, 1.6-2.6 mm long, glabrous, the lobes sometimes puberulent; stamen filaments 2.5-4.0 mm long, distinct; ovary glabrous to densely pubescent, on a stipe to 0.2 mm long. Legumes light brown to reddish brown, straight, flattened to slightly elliptic in cross section, not constricted between the seeds, oblong, 65-130 x 8-13 mm, coriaceous, reticulately striate, glabrous to densely puberulent, eglandular or covered with numerous very small reddish glands, indehiscent; stipe to 2 mm long; apex acute to obtuse. Seeds uniseriate, imbedded in a light brown pulpy material, brown, oblong to elliptic to oval, slightly flattened, 5.0-6.5 x 3.6-5.3 mm, smooth; pleurogram U-shaped to nearly oval, 2.5-4.0 mm across. Flowers from May to January. Chromosome number: Not determined.

Distribution

Shrubby vegetation, successional fields, edge of roads, thorn-scrub forests, dry forests, savannas, dry deciduous forests from sea level to 1700 m throughout northern and western South America from Venezuela to Peru.  Also known from the subtropical and tropical regions of North and Central America and the Caribbean Islands (Seigler & Ebinger 1988).

Additional info

Throughout its geographic range Vachellia macracantha is highly variable morphologically, numerous varietal and specific names have been applied to plants of this species (Bentham 1875, Isely 1973, Madsen 1990, Seigler and Ebinger 1988). This taxon is highly variable in the type and degree of pubescence on vegetative parts of the plant, ranging from glabrous to puberulent in most of Mexico and northern South America, to densely pubescent in the Caribbean Islands, to densely lanate throughout much of Chile, Ecuador and Peru. Also, leaf and leaflet size varies extensively.

Throughout northern South America (Columbia and Venezuela), and north through Central America, most individuals have leaves with 18 to 45 pinna pairs and the leaflets that exceed 3.0 mm in length; whereas is Chile, Ecuador and Peru many individuals have smaller leaves (12-20 pinna pairs) and leaflets (1.7-2.5 mm long). These characteristics are not consistent enough to distinguish separate varieties or subspecies, as many individuals with intermediate characteristics being encountered. Aronson (1991), while discussing the distribution of this species in Chile, mentioned that the "variability in size and shape of the pods, leaves, and stipular spines of V. macracantha has led to its being split into numerous regional taxa, many of which appear to be of dubious merit."

Vachellia macracantha specimens are usually cyanogenic.  In specimens from Mexico and Central America, Seigler and Ebinger (1988) found 89% were cyanogenic. Of the 230 specimens examined from South America, 91% tested positive for cyanide, usually strongly so. The compound proacacipetalin is responsible for this activity (Seigler et al. 1978, Seigler and Conn 1982).

Vachellia macracantha occasionally hybridizes with V. cochliacantha based on studies by Brimer et al. (1987). Also, Ebinger and Seigler (1987) found that this taxon hybridizes with V. pennatula, particularly in pastures and other disturbed habitats in the state of Veracruz, Mexico. Janzen (1974) suggested that V. macracantha may occasionally hybridized with various species of ant-acacia, particularly V. chiapensis. Ebinger and Seigler (1992) and Seigler and Ebinger (1995) reported that other taxa of the V. macracantha group hybridized with various ant-acacia species, but found no ant-acacia/V. macracantha hybrids.

Flowering time

May-January.

Representative specimens

WEST INDIES AND BAHAMA ISLANDS:

ANGUILLA:

ANTIGUA:

BARBADOS:

BAHAMA ISLANDS:

Great Inagua:

CUBA:

Prov. Oriente:

Prov. Granma:

DOMINICAN REPUBLIC:

Prov. Altagracia:

Prov. Azua:

Prov. Barahona:

Prov. Monte Cristi:

Prov. Pedernales:

Prov. Peravia:

Prov. Santiago:

Prov. Valverde:

Unknown:

GRENADA:

HAITI:

JAMAICA:

PUERTO RICO:

VIRGIN ISLANDS (US);

St. Croix:

St. John:

St. Thomas:

TORTOLA:

TRINIDAD:

TURKS AND CAICOS ISLANDS:

Grand Turk:

NORTH AND CENTRAL AMERICA:

UNITED SATES:

Florida:

Dade Co.:

Monroe Co.:

Polk Co.:

HONDURAS:

Choluteca:

MEXICO:

Campeche:

Chiapas:

Colima:

Guererro:

Jalisco:

Michoacán:

Nayarit:

Oaxaca:

Sinaloa:

Veracruz:

PANAMA:

SOUTH AMERICA:

CHILE:

Tarapacá:

COLOMBIA:

Atlántico:

Bolívar:

Cauca:

César:

Guajira:

Huila:

Magdalena:

Nariño:

Tolima:

Valle:

ECUADOR:

Azuay:

Carchi:

Chimborazo:

El Oro:

Esmeraldas:

Guayas:

Imbabura:

Loja:

Manabi:

Pichincha:

Zamora-Chinchipe:

FRENCH GUIANA:

GUYANA:

Guyana:

PERU:

Amazonas:

Arequipa:

Cajamarca:

Callao:

Cusco:

Huánuco:

Ica:

La Libertad:

Lambayeque:

Lima:

Moquegua:

Piura:

Tumbes:

TRINIDAD:

VENEZUELA:

Anzoátequi:

Aragua:

Bolívar:

Carabobo:

Falcón:

Federal:

Guárico:

Lara:

Mérida:

Miranda:

Monagas:

Nueva Esparta:

Sucre:

Zulia:

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